Wellbores are generally drilled into the ground or ocean bed to recover natural deposits of oil and gas, as well as other desirable materials that are trapped in geological formations in the Earth's crust.
In various oil and gas exploration operations, it may be beneficial to have information about the subsurface formations that are penetrated by a wellbore. For example, certain formation evaluation schemes include measurement and analysis of the formation pressure and permeability. These measurements may be useful in predicting the production capacity and production lifetime of the subsurface formation. Evaluating and/or measuring properties of encountered formations, formation fluids, and/or formation gasses may also be beneficial. An example property is the phase-change pressure of a formation fluid, which may be a bubble point pressure, a dew point pressure and/or an asphaltene onset pressure depending on the type of fluid. In some cases, a drillstring is removed and a wireline tool deployed into the wellbore to test, evaluate, and/or sample the formation(s), formation gas(es), and/or formation fluid(s).
Until a couple of decades ago, most of the wells drilled were vertical. Gravity and weight bars in the tool strings helped convey wireline (WL) tools rather easily in these wells. Today, the search for hydrocarbons has undergone a quantum leap in terms of the profile of the wells. Multi-laterals and horizontal wells are being drilled to boost oil recovery from the same reservoir. The technology required to convey tools in such wells has had to catch up to meet the growing needs of the industry. Tractors, Coil Tubings, High Strength Cables and TLC (Tough Logging Conditions) are now used to convey tools in such ultra-deep and extended reach wells. But these challenging environments posed even bigger challenges for conveyance operations. The cables saw increased torque, not just while tractoring in horizontal wells, but also in ultra-deep vertical wells. Previously, tension and compression in the cables were the only two parameters monitored in real time. But one other parameter, cable torque, is often not measured or monitored during the entire operation.